1. Field of the Invention
The present invention is related to a method for combining the internal and external insulating sleeves of an antenna for a communication instrument, and especially to a method for fast melting combining the internal and external insulating sleeves made of different material on a miniature antenna of a mobile phone in a mass production mode, this makes the combined structure more stable and reliable.
2. Description of the Prior Art
Conventional mobile phones generally are divided into a fixed and a stretchable type, no matter whichever type they are of, their antennae are destined to have the requirement to be miniaturized following the tendency of miniaturizing of the mobile phones. Particularly a fixed miniature antenna must have its electric coil, contact pieces for a receiving seat etc. densely mounted in the space between the internal and external insulating sleeves, and then the insulating sleeves can be processed for combining. Besides, although a stretchable antenna has structurally a longer stretchable antenna rod, it still has to be processed for combining of the base portion with the coil.
FIG. 1 shows a fixed miniature antenna of a mobile phone, it can be combined on the top of the mobile phone in a snap-in mode. Basically, such a fixed miniature antenna of a mobile phone is provided generally in the interior of the external insulating sleeve 10 thereof (namely, the exposed pipe of the antenna) with an internal insulating sleeve 11 for positioning therein a metallic receiving seat 12. The metallic receiving seat 12 is mounted thereon a coil 15 to cooperate with the inner upper surface 14 of the external insulating sleeve 10; while a lower portion 16 thereof can be mounted thereon an exposed elastic contact piece 17. In the presently used processing mode, the external insulating sleeve 10 having the inner upper surface 14 and a down facing opening 18 is combined with the internal insulating sleeve 11 by applying adhesive 19 therebetween after it is slipped over the internal insulating sleeve 11.
The presently used processing mode of applying adhesive between the internal and external insulating sleeves of a mobile phone has the following disadvantages:
1. The mode of applying adhesive often makes people wait for gluing, this results slow production speed, and the amount of adhesive applied and the area of gluing are uncertain, thereby, quality of combining is unstable.
2. Applying adhesive for combining at the combining areas of the internal and external insulating sleeves results inferior structural strength; they are no ideal in strength tests.
3. The chemical property of such adhesive generally may include corrosiveness; this may damage the whole antenna structure after a long period of use.
By virtue that the structural strength of the combining area between the internal and external insulating sleeves effected by the mode of applying adhesive is not as good as desired although it is faster in processing, the methods of processing available presently thereby also include injection enveloping and forming. However, the coil as stated in the above antenna structure must be uprightly held between the external insulating sleeve and the receiving seat. The method of injection enveloping and forming makes the spring coil enveloped and positioned in the interior extremely unstable, this results high rate of inferiority.
Another method of fix combining for the internal and external insulating sleeves of such an antenna is to provide a flange and a crevice respectively on the internal and external insulating sleeves to make their integral combination by press engagement. However, the structural strength of the whole antenna completed by such a combining method is still not ideal. And the speed of processing thereof is relatively slow by virtue that the flange must be pressed in the crevice.
Further, the internal and external insulating sleeves of the antennae of this kind generally are made of different material, for example, thermoplastic plastics is used for the external insulating sleeve, and polystyrene is used for the internal insulating sleeve. Thermoplastic plastics has a melting point of about 260xc2x0 C.-270xc2x0 C., while the melting point of polystyrene is about 190xc2x0 C.-200xc2x0 C., thereby, the internal and external insulating sleeves have never been combined by melting in the art.
The object of the present invention is to provide a method for combining the internal and external insulating sleeves of an antenna for a portable communication instrument. This method can make fast combining of the internal and external insulating sleeves which are slipped one over the other, the structural strength of the whole antenna completed by such a combining method is largely increased. The method of combining renders the processing faster, thereby is especially suitable for mass production, and working hour and cost of production can thus be reduced.
To obtain this object, the present invention is arranged to have the internal and the external insulating sleeves molten at their peripheries at the connecting area therebetween, then the internal and the external insulating sleeves are electrically turned on to transiently melt them together at a chosen temperature. The chosen temperature is about the value between the melting points of the two which are made of different material, while the time for the transient melting is within 1 second.
The present invention will be apparent in its novelty and other characteristics after reading the detailed description of the preferred embodiment thereof in reference to the accompanying drawings.